Controller, method of operating a water source heat pump and a water source heat pump

ABSTRACT

A controller, a water source heat pump and a computer useable medium are disclosed herein. In one embodiment the controller includes: (1) an interface configured to receive operating data and monitoring data from the water source heat pump and transmit control signals to components of thereof and (2) a processor configured to respond to the operating data or the monitoring data by operating at least one motor-operated valve of the water source heat pump via a control signal.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.16/694,381 filed Nov. 25, 2019 by Eric Perez et al. and entitled“Controller, Method of Operating a Water Source Heat Pump and a WaterSource Heat Pump,” which is a continuation of U.S. patent applicationSer. No. 15/861,881 filed Jan. 4, 2018 by Eric Perez et al. and entitled“Controller, Method of Operating a Water Source Heat Pump and a WaterSource Heat Pump,” now U.S. Pat. No. 10,495,248 issued Dec. 3, 2019,which is a continuation of U.S. patent application Ser. No. 15/162,813filed May 24, 2016 by Eric Perez et al. and entitled “Controller, Methodof Operating a Water Source Heat Pump and a Water Source Heat Pump,” nowU.S. Pat. No. 9,869,419 issued Jan. 16, 2018, which is a continuation ofU.S. patent application Ser. No. 13/627,438 filed Sep. 26, 2012 andentitled “Controller, Method of Operating a Water Source Heat Pump and aWater Source Heat Pump,” now U.S. Pat. No. 9,377,230 issued Jun. 28,2016, which claims benefit of U.S. Provisional Patent Application No.61/539,344, filed on Sep. 26, 2011 and entitled “Multi-Staged WaterManifold System for Roof Top Unit,” and U.S. Provisional PatentApplication No. 61/539,358, filed on Sep. 26, 2011 and entitled “ControlSystems for Multi-Staged Water Manifold System for Roof Top Unit,” whichall are incorporated herein by reference.

TECHNICAL FIELD

This application is directed, in general, to a water source heat pump(WSHP) and, more specifically, to a controller and control systems for aWSHP having a multi-stage fluid delivery system.

BACKGROUND

Water source heat pumps (WSHP) are presently used in large commercial orresidential buildings' cooling systems. These WSHP systems capture wasteheat from refrigeration-racks and use it to heat stores in winter,reduce peak loading in summer. Also, these systems are very similar tochiller systems that are also well known with the exception that theycan also run in a reverse cycle and function as a heat pump, therebyallowing them to function for both winter and summer heating/coolingapplications. Basically, the unit uses a refrigerating system to cool orheat water, which is used as a heat exchange mechanism to remove or addheat to the system. The water passes through a condensing coil andremoves heat from the heat refrigerant before passing through theexpansion valve. These units are desirable because they are moreefficient in heating and cooling large commercial or residential spaces,than standard cooling and heating systems. Though these units areeffective in providing heating and cooling to the building intended tobe cooled or heated, they are less efficient than desirable, givenpresent day concerns to reduce both power and water consumption.

SUMMARY

In one aspect the disclosure provides a controller. In one embodimentthe controller includes: (1) an interface configured to receiveoperating data and monitoring data from the water source heat pump andtransmit control signals to components of thereof and (2) a processorconfigured to respond to the operating data or the monitoring data byoperating at least one motor-operated valve of the water source heatpump via a control signal.

In another aspect, the disclosure provides a computer-usable mediumhaving non-transitory computer readable instructions stored thereon forexecution by a processor to perform a method for operating a watersource heat pump having at least one motor-operated control valve. Inone embodiment, the method includes: (1) receiving operating data andmonitoring data from the water source heat pump and (2) operating the atleast one motor-operated valve of the water source heat pump based onthe operating data or the monitoring data by transmitting a controlsignal thereto.

In yet another aspect, the disclosure provides a water source heat pump.In one embodiment, the water source heat pump includes: (1) acompressor, (2) a condenser being fluidly coupled to the compressor byrefrigerant tubing, (3) output conduit coupled to the condenser andbeing couplable to a distal location, (4) a modulating motor-controlledvalve interposed the output conduit, the modulating motor-controlledvalve configured to alter a flow of fluid through the condenser and (5)a water source heat pump controller configured to control operation ofthe modulating motor-controlled valve by varying a control signaltransmitted thereto based on operating or monitoring data received bythe controller.

BRIEF DESCRIPTION

Reference is now made to the following descriptions taken in conjunctionwith the accompanying drawings, in which:

FIG. 1 illustrates a schematic diagram showing the multi-stageconfiguration of the heat pump system as provided herein;

FIG. 2 illustrates a perspective view of one embodiment of a WSHPaccording to FIG. 1 ;

FIG. 3 illustrates a perspective view of one embodiment of the fluidcontrol system associated with the WSHP of FIG. 2 ;

FIG. 4 illustrates a block diagram of an embodiment of a controllerconstructed according to the principles of the disclosure;

FIG. 5 illustrates a flow diagram of an embodiment of a method ofproviding automated freeze protection of a water-cooled condenser;

FIG. 6 illustrates a flow diagram of an embodiment of a method ofproviding automated freeze protection for piping of the WSHP;

FIG. 7 illustrates a flow diagram of an embodiment of a method ofproviding automated freeze protection of a water-cooled condenser;

FIG. 8 illustrates a flow diagram of an embodiment of a method ofproviding automatic dynamic water flow control;

FIG. 9 illustrates a flow diagram of an embodiment of a method ofproviding leak detection;

FIG. 10 illustrates a flow diagram of an embodiment of a method ofproviding an automatic condenser anti-corrosion flush;

FIG. 11 illustrates a flow diagram of an embodiment of a method ofproviding supplemental heat;

FIG. 12 illustrates a flow diagram of an embodiment of a method thatprovides dehumidification for a WSHP;

FIG. 13 illustrates a flow diagram of an embodiment of a method ofproviding remote connection from the building water system;

FIG. 14 illustrates a flow diagram of an embodiment of a method ofproviding a high efficiency counter-flow heating mode;

FIG. 15 illustrates a flow diagram of an embodiment of a method ofproviding an automatic anti-water hammer feature;

FIG. 16 illustrates a flow diagram of an embodiment of a method ofswitching between air-to-air and air-to-water WSHP systems;

FIG. 17 illustrates a diagram of an embodiment of a drain panconstructed according to the principles of the disclosure;

FIG. 18 illustrates a diagram of an embodiment of a heat pump having anair-to-air heat exchanger and an air-to-water heat exchanger constructedaccording to the principles of the disclosure.

DETAILED DESCRIPTION

The disclosure provides a WSHP system with improved failure/protectionschemes. Additionally, the disclosure includes various control schemesto improve the performance of a WSHP system. A controller is disclosedthat is configured to direct the disclosed failure/protection schemesand improved operation schemes. In one embodiment, the controller is adedicated controller for the WSHP system. In another embodiment, thecontroller is a roof top unit (RTU) controller that is configured toinclude the necessary circuitry, operating instructions, or combinationthereof to perform the various functions described herein. In someembodiments, the different functions or schemes described herein may beperformed by various controllers. For example, a RTU controller and adedicated WSHP controller may each perform some of the disclosedfunctions or schemes.

FIG. 1 illustrates a schematic diagram of a multi-stage fluid controlsystem for a fluid WSHP unit 100 as covered by the embodiments discussedherein and which can be used in conjunction with a conventional roof topunit (RTU). For purposes of understanding this disclosure and claims, itshould be understood that the term “refrigerant” pertains to therefrigerant fluid flowing through the compressors 105, 110 and “fluid”pertains to any heat exchange fluid flowing through the condensers 115,120. This particular embodiment comprises compressor 105, 110 that areconfigured to operate in separate, heat exchange stages. The compressors105, 110, may be of conventional design and are operated in separatecycles, or when more than two compressors are present, multiplecompressors may be operated at the same time. For example, if fourcompressors are present, two compressors may be operated together in afirst operation cycle or stage, and the remaining two compressors may beoperated together in a second operation cycle or stage. Alternatively,the four compressors may operate in separate, first, second, third andfourth stages. As used herein and in the claims, “stage” means arefrigerant cycle operation where the compressor is operating andrefrigerant is passing through the associated condenser, and heatexchange is occurring between the refrigerant flowing through thecompressors 105, 110 and the fluid, such as water, glycol, or some otherknown heat exchanging fluid, passing through the condensers 115 or 120.

Condensers 115, 120 are each fluidly coupled to at least one differentcompressor 105 or 110 by refrigerant tubing 112, 114, to form separaterefrigerant cycles with the compressor to which the condenser 115, 120is coupled. In certain embodiments, each of the condensers 115, 120 iscoupled to a different compressor 105, 110, however, in otherembodiments, one of the condensers 115, 120 may be coupled to more thanone compressor. The condensers 115, 120 have intake ends coupledtogether by a fluid intake manifold 125. The manifold 125 is common tothe condensers 115, 120 and provides fluid flow into the condensers 115,120. Also, the condensers 115, 120 may be of conventional design, suchas concentric coil condensers, as those illustrated herein, or they maybe a conventional brazed-plate condenser. The condensers 115, 120 aredesigned to have separate refrigerant and fluid paths through which heatexchange occurs. Moreover, it should be understood that while only twocompressors and two condensers are shown, the present disclosure is notlimited to this particular numerical design and is expandable toaccommodate different heat/cooling needs of a given structure.

This embodiment further includes output conduits 130, 135, respectively,coupled to each of the condensers 115, 120. The output conduits 130, 135are couplable to a distal location, which is a location outside the heatpump system 100, such as a user's building water system including acooling tower or a RTU. The output conduits 130, 135 can be joinedtogether downstream from the condensers 115, 120 to provide a commonconduit to the distal location, as shown. Further included, is amodulating valve control system 140 interposed the output conduits 130,135. The modulating valve control system comprises separate modulatingvalves 140 a, 140 b that are interposed the conduits 130, 135 of therespective condensers 115, 120 with which it is associated. Modulatingvalves 140 a, 140 b are capable of proportionally controlling water bygoing from fully open to fully closed; or by going from a water flowsetpoint determined by a RTU unit controller to a closed position (nowater flow) determined by the RTU controller. Water setpoint is a flowin gallons per minute (GPM) or on a temperature drop (Delta T) throughthe water-cooled condenser. This value can either be factory set orfield/customer configurable. This represents a significant cost savingsby not having to have dedicated automatic temperature controllers(ATC's) or automatic temperature/flow controls on each water/refrigerantstage in addition to the motorized on/off shut off valve. Additionally,as explained below, in other embodiments, the modulating valve controlsystem 140 may also include a controller that can comprise one or moremicroprocessors and is configured to control the operation thereof. Themodulating valve control system 140 is configured to control a flow offluid through the condensers 115 or 120, based on the required operationof the compressor 105 or 110 to which the condenser 115 or 120 isrespectively coupled.

For example, in a stage 1 heat exchange cycle and just before thecompressor 105 is activated, a signal goes out to the modulating valvecontrol system 140 from a controller, which causes the valve 140 a toopen. This allows a flow of fluid to begin flowing through condenser 115for a short period of time and charge the condenser 115 with fluid.Following this brief period of time, compressor 105 is then activated.During stage 1, valve 140 b remains in the closed position, as long asthere is not a need to activate compressor 110 with which condenser 120is associated, thereby preventing a flow of fluid through condenser 120.However, if there is a call from a controller for stage 2 operation, asignal goes out to the modulating valve control system 140, which causesthe valve 140 b to open, just prior to the activation of compressor 110,which allows condenser 120 to be charged with fluid. The opening of thevalve 140 b allows a flow of fluid through condenser 120 during theoperation of compressor 110. Thus, where there is only a need for stage1 operation, fluid is flowing only through the condenser 115, which isassociated with compressor 105. Alternatively, when there is a need forboth stage 1 and stage 2 operation, fluid is flowing through both of thecondenser 115, 120 during the operation of compressors 105, 110.

In view of the above, fluid flow through the condensers 115, 120 iscontrolled by the valve control system 140 in such a way that only thefluid that is needed to meet heating/cooling requirements is pumpedthrough the condenser associated with the operating compressor. This isin stark contrast to conventional, single stage systems where fluidflows through each condenser regardless of which compressor stage isoperating. In such conventional systems, no staged multiple valvecontrols are present, so fluid is flowing through all the condenserswhen any one of the compressors is operating. As such, there is nostaging of fluid flow through the condensers with the operation of thecompressors. As a result, all of the fluid pumps run at all times duringthe operation to maintain the required pump pressure within the system.This constant pump operation requires more pump energy than theembodiments provided by this disclosure.

In operation, fluid, such as water from a distal location, is pumpedtoward the WSHP unit 100. In a cooling operation mode, the refrigerantwithin each refrigeration circuit leaves the associated compressor as ahot gas. When the hot refrigerant gas passes through the refrigerantpath within condensers 115 or 120, it transfers heat to the fluid thatflows through a fluid path within the condensers 115 or 120. Therefrigerant becomes cooler and turns to a liquid state before passingthrough an expansion vale, not shown, after which it quickly expandsinto a cold gas as it passes through an evaporator or indoor coil asseen in FIG. 2 , as described below. Of course, in a heating mode, theabove described cycle is reversed to provide heat to the indoor coils.

As noted above each stage 1 (compressor 105 and condenser 115) and stage2 (compressor 110 and condenser 120) has separate modulating controlvalves 140 a and 140 b associated with them. As such, these modulatingcontrol valves 140 a and 140 b control the fluid through the condensers115, 120 in a staged manner, such that only the condensers associatedwith active refrigeration circuits have refrigerant and fluid passingthrough them. Moreover, modulating control valves 140 a and 140 b can bespecifically designed to include a motorized actuator, automatic flowcontrol, and 3-way valves (for by-pass). In such embodiments, themotorized actuators are opened when the respective compressors areenergized with thermostat demand signals Y1, Y2, . . . and W1, W2 . . ., etc. The condensers 115, 120, which are, in certain embodiments,arranged in a parallel arrangement, are coupled together by the manifold125 so that fluid is able to flow though only the condenser that has anactive refrigeration circuit. Thus, a matching in refrigerant flow withfluid flow can be achieved, and only fluid that is doing the work willbe pumped at any given point in time. Moreover, these systems canprovide a variable flow rate and allow the flow rate to be staged tocoincide with the number of active compressors within the system at anygiven point in time, which provides significant pump volume and energysavings. The flow rate is reduced and that in turn has a significantimpact to the pump horsepower, which results in energy savings.

With the present disclosure, it has been found that staging the fluidthrough the condensers 115, 120 provides a system that saves energy, byreducing the fluid required to run the pumps by up to about 50% in partload conditions in a two-compressor system. This translates to about 86%savings in pump energy, when using a typical speed controlledcentrifugal pump water system. Moreover, in a four-compressor system,flow rate reduction can be increased further, even up to about 75%,which can translate into as much as about 97% savings in pump energy,when using a typical centrifugal pump water system. As such, this uniqueconfiguration allows not only a reduction of fluid flow but asignificant pump energy savings over conventionally designed systems.

FIG. 2 illustrates one configuration of the WSHP system 100, asgenerally discussed above. In this embodiment, a WSHP unit 200 includesa housing frame 202 on which the various components of the WSHP system200 are placed, and the condensers mentioned above regarding FIG. 1 arewater condenser coils 204, 206, wherein each of the condenser coils 204,206 includes two coils. The condenser coils 204, 206 may be ofconventional design with each of the dual coils comprising twoconcentric tubes that form a separate refrigerant path and fluid pathwithin them. As shown, condenser coil 204 is coupled to compressor 208by refrigerant tubing 210 to form a first refrigerant cycle, or stage 1,and condenser coil 206 is coupled to compressor 212 by refrigeranttubing 214 to form a second refrigerant cycle, or stage 2. Though onlytwo compressors and two coils are shown, it should be understood thatthe system can be expanded to include multiple coils and compressors ina 1:1 coil/compressor ratio. As such, the system can easily be expandedfor increased capacity as design requires.

The two above-mentioned stages share a common intake water manifold, notshown in this view that is located at the bottom of the condensing coils204 and 206 and supplies water to both coils. The first and second stagecondensing coils 204, 206 form separate fluid paths and the water,though taken in through the common manifold, is not intermixed once thefluid enters each of the stage 1 and stage 2 coils 204, 206. The stage 1and stage 2 condensing coils 204, 206 are comprised of concentric tubesin which the most center tube forms the water path and the outer, largerconcentric tube forms the refrigerant path. The temperature differencebetween the refrigerant and water flowing through the concentric tubesallows for the heat exchange to occur. The operations of the WSHP unit200, as described herein, are controlled by a unit controller 216 andcan include the programming and one or more microprocessors andmicrocircuits boards necessary to implement the embodiment describedherein.

Compressors 208 and 212 are fluidly connected to an indoor evaporatorcoil 218 through which air is directed by a motor 220 and fan 222through filter 224 and an optional economizer damper 226. Theillustrated embodiment also includes a conventional first chargecompensator 228 associated with compressor 208 and a conventional secondcharge compensator 230 associated with compressor 212. The compressors208 and 212 also have first and second reverse valves 232, respectivelyassociated therewith to allow the refrigerant flow direction, andsubsequently the refrigeration cycle in the unit to be operated inreverse. The unit 200 further includes the valve control system 234,conduit system 236, including water input and outputs 238, 240, whichare explained in more detail below.

FIG. 3 is a partial view of the WSHP unit 200 of FIG. 2 that illustratesthe condensers, conduits, and valve control system 300 of the WHSP unit200. The drain pan 9 illustrated in FIG. 17 can be positioned underthese components of the WSHP to aid in leak detection. In thisembodiment the system 300 has a two-stage quad condensing coilconfiguration wherein each stage includes two condensing coils 302, 304.This embodiment further illustrates a common water inlet point 306 thatis couplable to a water source from a distal use point, such as a user'sstructure or cooling tower. The water can pass through a three-way valve308 that is positioned in a by-pass position 310 or a main loop position312. The three-way valve 308 is connected to a strainer 314 that movesforeign debris from the water flowing through the system 300. Conduitpipe 316 leads from the strainer 314 to a manifold 318 that feeds boththe condensing coils 302, 304. The stage 2 coil 302 is connected by aconduit 320, on its outlet side, to a stage 2—flow control valve 322,and the stage 1 coil 304 is connected by conduit 324, on its outletside, to a stage 1 flow control valve 326, as shown. The separate outletconduits 320 and 324 and control valves 322 and 326 allow for a stagingof the water flow through the WSHP system 200 of FIG. 2 , as explainedabove. Once the water passes through either one or both of the controlvalves 322, 326, it passes through air event sections 328, 330, afterwhich, conduits 320 and 324 merge into a single conduit 332. Using themotor actuator control valves 322, 326, to control water flow allows thebenefit of not using a flow regulator on each of the stages. The waterthen passes through three-way valve 334 and to the distal point of use,provided the three-way valve 334 is in a main loop position 336.However, if the three-way valves 334 and 308 are in the by-pass position338 and 312, the water travels through the flexible hose 340 and backout of the unit, by-passing the condensers, conduits and valve controlsystems. As described below in different control schemes, the three-wayvalves 308, 334, can be controlled by a controller to move the valvesinto the various positions. In FIG. 3 , the three-way valves 308, 334,are illustrated as manual valves to show the various positions. Each ofthe three-way valves 308, 334, is also a controllable valve as thevalves 322, 326, and both include a motorized actuator as illustrated inFIG. 3 with valves 322, 326. The motorized actuators for valves 322,326, are represented by elements 309 and 335, respectively, wherein thearrows indicate the valves that are controlled. In one embodiment, acontroller can send a 0-10-volt signal to direct the actuators to causethe three-way valves 308, 334, to move to desired positions. Forexample, the three-way valves 308, 334, can be remotely controlled toconnect or disconnect the WSHP system 300 from a water source such asthe building's water system and provide different modes of operation.By-pass mode provides advantages during water system commissioning andstart up, by allowing external water-loop connections in the building tobe pressure checked, flushed and drained without exposing any of theflow control and condenser heat exchanger to potentially damaginghigh-air pressures. It's common practice to use high pressure andnon-chemically treated water to flush contaminants from the buildingwater loop piping systems during the startup process. If the WSHP isleft connected during the flushing process there is the potential toexpose the WSHP to a high concentration of contaminants and cleanerscould potentially damage the copper and brass materials that arecommonly used in water cooled condenser flow control and heat transfersystems. Another advantage of having a flow-control system w/a built-inbypass mode is the ability to repair and/or replace systems downstreamof the main water loop w/o having to disconnect the connection pointsbetween the building's main water loop and the RTU.

The foregoing embodiments disclose an improved WSHP that allows stagingof the condensers in tandem with only the compressors that areoperating. This reduces pump energy in that pump pressure is reduced andallows significant savings in energy costs and water consumption in theoperation of the WSHP unit. Moreover, this savings in pump energy,derived from restricting fluid flow to non-active condenser circuitsdoes not impact the operations efficiency of the refrigeration system.

FIG. 4 illustrates a block diagram of an embodiment of a controller 400constructed according to the principles of the disclosure. Thecontroller 400 is configured to direct the operation of or at least partof the operation of a WSHP system, such as the WSHP system of FIG. 100,200 or 300 . As such, the controller 400 is configured to generatecontrol signals that are transmitted to the various components to directthe operation thereof. The controller 400 may generate the controlsignals in response to feedback data that is received from varioussensors and/or components of the WSHP system, such as water/moisturesensors, float-switches, temperature sensors and accelerometers. Thesensors can be conventional sensors that are positioned in the WSHPsystem, RTU or enclosed space being cooled/heated and connected to thecontroller 400 via conventional wired or wireless means. One skilled inthe art will understand the use, positioning and attachment of thevarious sensors that are used to provide data to the controller 400 asinput for the controller to use to direct the operation of the WSHPsystem. The controller 400 includes an interface 410 that is configuredto receive and transmit the feedback data and control signals. Theinterface 410 can also be configured to receive programming data fordirecting the operation of a WSHP system. The interface 410 may be aconventional interface that is used to communicate (i.e., receive andtransmit) data for a controller, such as a microcontroller.

The controller 400 also includes a processor 420 and a memory 430. Thememory 430 may be a conventional memory typically located within acontroller, such as a microcontroller, that is constructed to store dataand computer programs. The memory 430 may store operating instructionsto direct the operation of the processor 420 when initiated thereby. Theoperating instructions may correspond to algorithms that provide thefunctionality of the operating schemes disclosed herein. For example,the operating instructions may correspond to the algorithm or algorithmsthat implement a method or methods of operation illustrated in FIGS.5-16 . The processor 420 may be a conventional processor such as amicroprocessor. The interface 410, processor 420 and memory 430 can becoupled together via conventional means to communicate information. Thecontroller 400 can also include additional components typically includedwithin a controller for an HVAC system, such as a power supply or powerport.

The controller 400 is configured to provide and operate the WSHP systemaccording to various operating schemes including protection schemes. Inone embodiment, the controller 400 is configured to provide automatedfreeze protection of a water-cooled condenser in the roof top unit (RTU)using a temp-sensor to determine when freezing conditions areapproaching regarding the water-cooled condenser. In such instances, thecompressor in RTU (in cooling mode) is turned on to raise discharge tempand temperature in the condensing coil to prevent freezing. The freezeprotection system may have adjustable set-points as well as anadjustable service-relay output to allow the unit to go into cooling fora short time to help the coil from freezing. Such embodiments providethe benefits of cost reduction, improved reliability, and theelimination of an ambient heater, all of which provides both cost andenergy savings. Thus, the controller 400 is configured with thenecessary operating instructions (e.g., stored in the memory 230) toreduce energy consumption.

In another embodiment, controller 400 is configured to provide anautomated freeze protection system for the piping in a closed-loop watersource heat pump. In such systems, the compressor is operated in acooling mode, to transfer refrigerant heat to the closed loop water coilpiping system that may serve multiple RTU's. The controller 400, whichcan be employed in the WSHP system or a separate controller, can beprogrammed to cycle a gas-fired heat exchanger associated with the RTUto re-heat the supply air back to the heating setpoint. This system caneasily be automated, linked to enter water temp at the RTU, or can beinitiated by the building management system and an HVAC controlinterface. Such an embodiment can provide cost reduction, elimination ofa gas-fired boiler in a close-loop water system, improvement inreliability, simplification of the water source system and theelimination of boiler maintenance, thereby reducing installation costsassociated with the installation of the WSHP.

In another embodiment, the controller 400 is configured to provide anautomated ambient heater control feature in RTU controller can beincluded to prevent the water in the condenser coil from freezing whenit is turned off and it's below freezing outside. This embodiment canalso provide the benefit of reducing energy consumption.

In another embodiment, the controller 400 is configured to provide anautomatic dynamic water flow control. In this embodiment, the controller400 can be used to maintain a constant temperature change across thewater-cooled condenser coil by sending a 0-10V signal to a fullymodulating actuator controlling an adjustable ball-valve such as 322 and326 in FIG. 3 . Additionally, the controller 400 can be used to increasewater flow in part-load conditions and allow field selectabletemperature delta temperature both for part-load and full-load coolingdemands through the implementation of an appropriate algorithm stored inthe memory 430 of the controller 400 or a separate controller. Thisembodiment provides the benefits of cost reduction, elimination of aflow-cartridge, reduction of pressure drop and reduced pump energy,flexibility of installations with varying water flow rates, increasedefficiency when extra pump energy is available during part-load coolingoperation, and the prevention of the fluctuation in pump head pressurefrom affecting unit performance.

In another embodiment, the controller 400 is configured to provide anautomatic emergency water shut-off feature. One aspect of thisembodiment employs a sensor in the water-cooled condenser compartment.If water is sensed in the compartment, the controller 400 is configuredto close the water intake valve 308 to position 312, and outlet valve334 to position 338 and send an emergency signal to the building controlsystem (e.g., a management system). This particular embodiment providesthe benefits of improved system reliability, active leak detection andreporting, prevention of leakage of fluid used in closed loop condensersystems from draining into a membrane roof or going into a storm run-offsystem, prevention of a leak in a single unit from escalating into aclosed-loop system shutdown, and the prevention of leaking fluid downinto store, through pipe connection area. A drain pan as illustrated inFIG. 17 can be employed with this function of the controller 400.

In another embodiment the controller 400 provides an automatic condenseranti-corrosion flush-cycle that can be implemented by sending a 0-10Vsignal to a fully modulating actuator 322 add 326 controlling anadjustable ball-valve. The processor 420 can interactive with analgorithm written in the memory 430 to configure the actuator to openand close a water-cooled condenser at timed intervals to preventcorrosion and scaling associated with long-term standing water, whichcan have a negative effect on system performance/efficiency. Thisembodiment provides the benefits of preventing deposits and scale incondenser coils that could lead to early replacement of condenser coils,and helps maintain uniform water chemistries in closed-loop water cooledsystems.

In another embodiment the controller 400 provides an automatic emergencyheat mode for the WSHP unit. In this embodiment the controller 400automatically brings in supplemental heat in case the unit is unable tosatisfy the buildings heating load and/or supply temporary emergencyheat. When the WSHP unit enters emergency heat mode, a signal will beissued to the building management system to alert them of lack ofheating capacity. The building management system alert can be toggled onor off at the controller 400. Supplemental heat can then be deliveredwith either electric resistance elements or a gas-fired combustion heatexchanger. This embodiment provides the benefits of increased customercomfort, the elimination of no-heat conditions, redundant heatingcapability for WSHP's, allows higher peak heating loads on closed loopsystems, and replaces the need to have a boiler, thereby reducing costs.

In another embodiment the WSHP system includes a humidifier, such asthose disclosed in U.S. Pat. Nos. 6,427,461, 6,664,049, 6,826,921, and7,823,404, and U.S. patent application Ser. No. 12/888,952, filed Sep.23, 2010, entitled Air Conditioning System With Variable CondenserReheat And Refrigerant Flow Sequencer, which are incorporated herein forall intents and purposes. The humidifier component of the WSHP system isconfigured to dehumidify the air during either heating or cooling cyclesby utilizing a row split indoor coil and a water-cooled condenser coil,thereby providing a dual-purpose unit with reheat and heat pumpcapabilities in the same unit. The controller 400 is configured tocontrol this embodiment that provides the benefits of increased customercomfort, allows the air conditioning system to operate to reducehumidity in the occupied space without over cooling the space and allowsWSHP units to be used in higher humidity environments.

The WSHP disclosed herein is a smart water flow system with smartactuators 322, 326, 335 and 309 that can be operated based on a controlsignal. The control signal can operate the smart valves between fullyclosed or fully open or an opening range of 0-100% based on a voltage ofthe signal. As such, water flow can be changed in the WSHP remotely.Different valves can be operated to alter flow, stop flow and/or bypassflow of water through the WSHP. These valves can be controlled todetermine the operation of the WSHP. The smart valves can be modulatingmotor-controlled valves that employ an actuator for opening and closingthe valve. Such conventional modulating valves can be used herein.

In addition to the operating schemes mentioned above, FIGS. 5-16illustrate flow diagrams of embodiments of methods of operating a WSHPsystem according to the principles of the disclosure. In at least someof these methods, smart valves are used to perform the variousoperations or features. The FIGS. 5-16 provide more details of operatingschemes noted above or provide additional operating schemes. For eachmethod, the HVAC system can be a WSHP as illustrated in FIGS. 1-3 andthese figures are referred to in the various methods. The WSHPs of FIGS.1-3 include two stages. One skilled in the art will understand that theprinciples of the disclosure apply to smart valve WSHPs that have onlyone stage or more than two stages. For example, for a one stage, smartvalve WSHP, three smart valves can be used, such as modulatingmotor-operated valves 322, 308 and 334. For a four stage, smart valveWSHP, six smart valves can be used; two such as 308 and 334, plus foursimilar to 322 or 326. The controller 216 in FIG. 2 may be configured toperform each of the methods of operation.

FIG. 5 illustrates a flow diagram of an embodiment of a method 500 ofproviding automated freeze protection of a water-cooled condenser. Themethod 500 begins in a step 505.

In a step 510 water temperature in the condenser coil is compared to afirst set point. The first setpoint is selected to prevent freezing ofwater in the condenser coil and is selected based on when freezingconditions are approaching. For example, a first set point of 40 degreesFahrenheit can be selected in order to take measures to prevent freezingbefore approaching the freezing point of 32 degrees Fahrenheit. Asmentioned previously, the water in the condenser coil can also bereferred to as fluid whereas the liquid in the compressor is referred toherein as a refrigerant. Thus, the water or fluid in the condenser coilcan include an antifreeze and the first set point can be selected basedon a percentage of the antifreeze in the water and the type ofantifreeze.

If the water temperature is above the first set point the methodcontinues to step 510. If the water temperature is not above the firstset point the method continues to step 530 where the water valve isopened to a slow setting and to circulate warm water from the closedwater loops to the water-cooled condenser coil. The valves 322, 326, areopened automatically via control signals and in one embodiment will opento 25% of the normal heating position or equivalent of half a gallon perminute (½ GPM) or GPM per ton of RTU capacity.

A determination is then made if the water temperature in the condensercoil is below a second set point in a step 540. The second set point hasa lower value than the first set point and is used to initiateadditional measure to prevent freezing of the condenser coil. The secondset point can be, for example, 36 degrees Fahrenheit. Again the amountand type of antifreeze can be considered when determining the second setpoint. If not, the method continues to step 545 where the water valve isopened to the normal flow setting, which is determined by valve openingposition that corresponds to normal heating position or equivalent of 2GPM/Ton of refrigeration. This will increase the water flow goingthrough the condenser coil and, ideally, increase the heat. Adetermination is then made in a third decisional step 547 if the watertemperature in the condenser coil is above the first set point. If so,the method continues to step 510. If not the method continues to step540.

At step 540, if the water temperature in the condenser coil is below thesecond set point, the method continues to step 550 where the water valveis closed and compressors 1 and 2 are started. Thus, instead of usingheat from the stored water system, the water valves are operated to useheat from the refrigeration system. As such, the controller operates thevalves to disconnect from the stored water system.

In a step 560, a coil low-temp alarm is sent to the management system.The management system may be a building management system wherein theWSHP is installed. In response to the coil low-temp alarm, a person,e.g., a repairman, is typically sent to visually check the WSHP. Themethod ends in a step 570.

FIG. 6 illustrates a flow diagram of an embodiment of a method 600 ofproviding automated freeze protection for piping of the WSHP. Method 600operates when the WSHP is in the heating mode, e.g., an enclosed spaceis being heated. Since heat is being extracted from the water in theheat mode, then the water can freeze in the WSHP even if above freezingbefore entering the system. As such, the method 600 considers the watertemperature before entering the condenser coil. The method 600 begins ina step 605.

In a step 610, the temperature of water entering the condenser coil iscompared to the setpoint. The set point can be predetermined based onhistorical data and can be selected or modified considering real timedate such as the present operating modes, temperature of the enclosedarea, etc.

A determination is made in a first decisional step 620 if the WSHP is aheat mode. If not the method continues to step 610. If in heat mode, themethod continues to step 630, and the water valve is opened for normalwater flow. A determination is then made in a second decisional step 640if the water temperature entering the condenser coil is below the setpoint. If not the method continues to step 630. If so, the methodcontinues to step 650 where the gas fired heat exchanger (see FIG. 2 forexample) is started and the discharge air temperature control mode isinitialized. Discharge air temperature control mode uses discharge airtemperature at the supply duct to determine the amount of supplementalheat is required to maintain a comfortable discharge air temperature.Gas Heat exchanger is cycled from off/low-heat and high-heat to keepdischarge air temperatures at or near a desired set point.

In step 660, the WSHP is switched into cooling mode once the heatingsystem is on-line. As soon as the hot discharge gas from compressorsenters the condenser coil, heat is being pumped back into the WSHPsystem and heating the water-cooled condenser while also heating theenclosed space. The WSHP boiler mode is when the RTU is in cooling mode,supplemental heating is used to temper discharge air with eitherresistant heaters or a gas-fired heat exchanger. A determination is thenmade in a step 670 if the entering water temperature is below the setpoint. If so the method 600 continues to step 660. If not, the methodcontinues to step 680 and terminates the WSHP boiler mode. The method600 then ends in step 690.

FIG. 7 illustrates a flow diagram of an embodiment of a method 700 ofproviding automated freeze protection of a water-cooled condenser.Unlike method 500, method 700 includes the use of ambient heat such asresistance heating. The method 700 begins in a step 705.

In a step 710 water temperature in the condenser coil is compared to afirst set point. As noted above, the first set point is selected toprevent freezing of water in the condenser coil and is selected based onwhen freezing conditions are approaching. The first and second set pointof method 700 can be the same set points that are used for method 500.If the water temperature is above the first set point as determined instep 720, the method 700 continues to step 710. If the water temperatureis not above the first set point as determined in step 720, the method700 continues to step 730 where the water valve is opened to a slowsetting and to circulate warm water from the store to the water coil.The valves 322, 326, are opened automatically via control signals.

A determination is then made if the water temperature in the condensercoil is below a second set point in a step 740. If not, the methodcontinues to step 745 where the water valve is opened to the normal flowsetting. This will increase the water flow going through the condensercoil and, ideally, increase the heat. A determination is then made in athird decisional step 747 if the water temperature in the condenser coilis above the first set point. If so, the method continues to step 710.If not the method continues to step 740.

At step 740, if the water temperature in the condenser coil is below thesecond set point, the method continues to step 750 where ambient heatingis turned on. The ambient heating can be resistance heaters positionedclosed to the condenser coils to provide heat and prevent freezing.

In a step 760, a coil low-temp alarm is sent to the management system.The management system may be a building management system wherein theWSHP is installed. In response to the coil low-temp alarm, a person,e.g., a repairman, is typically sent to visually check the WSHP. Themethod ends in a step 770.

FIG. 8 illustrates a flow diagram of an embodiment of a method 800 ofproviding automatic dynamic water flow control. In method 800, acontroller is employed to maintain a constant water temperature dropacross the water-cooled condenser. The valves 322 and 326 will beoperated in PID loop to maintain delta-t close to a constant temperaturedrop (e.g., within a range of four degrees with this value being fieldadjustable) across the water-cooled condenser coil by adjusting thewater flow. The method 500 begins in a step 805.

In a step 810, a comparison is performed between water temperatureentering and exiting the condenser coil. Conventional temperaturesensors can be employed at the entrance and exit of the condenser coilto provide the temperatures for comparison for each refrigerant stage. Adetermination is then made in a decisional step 820 if the temperaturedifference is at the set point. The set point represents the targetvalue plus the determined range. For example, with a total range of fourdegrees, and a set point of 15 delta-T, then measured value can be from13 F to 17 F before the system will try to readjust the valve position.This is done to prevent the valves 322 and 326 and the pump system inthe closed loop from trying to overcorrect for minor pressurefluctuations in head pressure. The range can be adjusted to better adaptthe WSHP controller to the dynamics of a pump package. If thetemperature difference is at the set point or within an acceptable rangeof the set point (one or two degrees, for example), then the methodcontinues to step 830 and ends. If not at the set point or within anacceptable range, then the method continues to step 825, and the controlvalve is operated to adjust water flow through the condenser coils. Thecontrol valves, for example, are valves 322 and 326 in FIG. 3 and can beadjusted to control the amount of water flowing through the condensercoil. A higher water flow rate can lower the temperature differencewherein a lower water flow rate can increase the temperature difference.

FIG. 9 illustrates a flow diagram of an embodiment of a method 900 ofproviding leak detection. The method 900 can be used with a drain panhaving a recessed area. An example of such a drain pan 9 is illustratedin FIG. 17 . The drain pan 9 is typically located under the water pipingand condenser coils of the WSHP system. The drain pan 9 can be made froma metal or a plastic. The drain pan 9 includes a recessed area 10, anangled area 11 and two moisture sensors or float switches, 12 and 13.The first moisture sensor 12 is located in the recessed area 10 and thesecond moisture sensor 13 is located in the angled area 11. The drainpan 9 is configured to catch water or fluid. The angled area 11 istilted such that water flows to the recessed area 10 when landing on theangled area 11. The recessed area 10 is configured to hold a minimalamount of water, e.g., a cup. Thus, the first sensor 12 can provide anearly warning of a water leak. Both the first and second sensors 12, 13,are coupled to a controller, such as the controller 216, through eithera wired or wireless connection. The sensors 12, 13, can be conventionalmoisture sensors and can be attached to the drain pan 9 in aconventional manner.

Turning back to FIG. 9 , the method 900 begins in a step 905. Adetermination is then made in a first decisional step 910 if a firstwater (or moisture) sensor is tripped. If not, the method continues tostep 910. If it is tripped, e.g., moisture is present in the recessedarea 10, a maintenance alarm is sent to a management system and amaintenance timer is started.

A determination is then made in a second decisional step 940 if themaintenance timer has expired. The time set for the maintenance timer isfive hours minutes in one embodiment. The amount of time set on themaintenance timer can vary depending on the installation or selectedmaintenance procedures. If the maintenance timer has not expired, thenthe method continues to step 910. If the maintenance timer has expired,then the method 900 continues to step 950 and a water leak alarm is sentto the management system.

A determination is then made in a third decisional step if a secondwater sensor has tripped in a step 960. If not, then the methodcontinues to step 910. If so, then overflow alarm is sent to themanagement system in a step 970. The method 900 then continues to step980 where the WSHP is automatically disconnected from the water systemof the building. For automatic disconnection, a control signal can besent to three-way valves, such as valves 308 and 334 of FIG. 3 , todisconnect the WSHP from the building water. In some embodiments, thethree-way valves are spring loaded and automatically disconnect from thebuilding water when power is lost to the WSHP.

FIG. 10 illustrates a flow diagram of an embodiment of a method 1000 ofproviding an automatic condenser anti-corrosion flush. The method 1000opens and closes at timed intervals to prevent corrosion and scalingassociated with long-term standing water. In one embodiment, amodulating actuator controlling an adjustable ball-valve, such as valve322, 326, in FIG. 3 , is employed. A WSHP can have multiplerefrigeration stages wherein some of the stages are not operated on aregular basis. As such, the method 1000 moves water through thecondenser coils of the different stages to prevent corrosion and/orscaling that can occur due to inactivity. The method 1000 begins in astep 1005.

In a step 1010, idle timers are started for each refrigeration stage ofthe WSHP. Thus, if there are four refrigeration stages, then four timersare started wherein each stage has their own timer. The amount of timeon each timer can be the same or, in some embodiments, can differ basedon expected or historical use.

In a step 1020, a determination is made in a first decisional step if atimer has expired. If so, the method continues to step 1030 and cycleswater through the corresponding condenser coil of the expired timer. Thewater can be cycled through the condenser for a set amount of time. Inone embodiment, the amount of time is one minute. The expired timer isthen reset in step 1040. Typically, the expired timer is set to itsoriginal value. The method 1000 then ends in step 1050.

Returning now to step 1020, if a timer has not expired, a determinationis then made in a second decisional step 1025 if one of therefrigeration stages has operated. If so, the method continues to step1040 and the timer for the operated stage is reset. If not the method1000 continues to step 1020.

FIG. 11 illustrates a flow diagram of an embodiment of a method 1100 ofproviding supplemental heat. The method 1100 can automatically bring insupplemental heat when the WSHP is unable to satisfy a building'sheating load and/or supply emergency heat. When the WSHP unit entersemergency heat mode, a signal can be issued to a management system toalert maintenance of a lack of heating capacity. The alert can betoggled on or off at the controller. Supplemental heat can be deliveredwith either electric resistance elements or a gas-fired combustion heatexchanger. The method 1100 begins in a step 1105.

In a step 1110, a determination is made if the WSHP is in heat mode. Ifnot the method continues to step 1110. If so, the method continues tostep 1120 where a determination is made on how many degrees differencethere is between the thermostat set point in the occupied space the WSHPis heating and the actual measured temperature in the occupied space.Default value is 5 F difference between setpoint and actual temperature,which is a value that is field adjustable.

If not the method continues to step 1110. If so, a determination is madein a third decisional step if the WSHP has been running at high heatmore than a predetermined number of minutes T. In one embodiment, T is60 minutes. If not, the method continues to step 1120. If so, the methodcontinues to step 1140 where the supplemental heat is turned-on. Themethod 1100 then ends in a step 1150.

FIG. 12 illustrates a flow diagram of an embodiment of a method 1200that provides dehumidification for a WSHP. The method 1200 allows theWSHP to dehumidify while heating or cooling by utilizing a row splitindoor coil and a water-cooled condenser coil. As such, the WSHP becomesa dual-purpose unit with reheat and heat pump capabilities in the sameunit. The method 1200 begins in a step 1200 when a determination is madethat dehumidification is needed.

In a step 1210, a determination is made that dehumidification is needed.The determination can be based on humidity sensors located in thebuilding. Conventional humidity sensors can be employed.

In a step 1220, the WSHP is operated in dehumidification mode whereinstage 1 is operated in a cooling mode and stage 2 is operated in aheating mode. Thus, in contrast to a heating mode wherein both of thestages would be operating in heating mode, the valve (e.g., valve 232 inFIG. 2 ) for stage 1 is reversed. Thus, air is reheated to allow coolingto remove humidity. The various sensors or controls needed to determinethat dehumidification is needed and to manage the dehumidification canbe the same ones used for humidity control described in the patents thatare referenced above. The method ends in a step 1220.

FIG. 13 illustrates a flow diagram of an embodiment of a method 1300 ofproviding remote connection from the building water system. Similarly,the method 1300 can be used to disconnect the WSHP from the buildingwater system. Wireless or wired connections can be employed to connect aWSHP to a management system such as a building management system at aninstallation. The method 1300 begins in a step 1305.

In a step 1310, the WSHP is remotely connected to the building's watersystem. Three-way valves, such as valves 308, 334 in FIG. 3 can becontrolled remotely to provide the connection. As such, water from thebuilding enters the water manifold of the WSHP. In a step 1320, the WSHPsystem is checked. Various sensors, such as moisture sensors 12 and 13mentioned above, are used to determine if there are any leaks. A commandcan be sent to the management system indicating that there are no leaks.After checking the WSHP system, an automated start-up process begins instep 1330. The controller goes through a pre-programmed process, checksoperation of all or at least most of the components—and modes of theWSHP. The controller checks, for example, sensors, economizer,compressors, reversing Valves, blowers, water delta-T, pressure's etc.The controller can then send a report through a connection to themanagement system or another desired location. Additionally, the reportcan be loaded to a USB. The method then ends in a step 1340.

FIG. 14 illustrates a flow diagram of an embodiment of a method 1400 ofproviding a high efficiency counter-flow heating mode. The WSHP iscapable of reversing water flow in a heating mode to maximize heattransfer in cooling and in heating by employing counter-flow for theheating cycle, also. Typically, a WSHP is optimized to provide thehighest efficiency (counter-flow) in the cooling mode when hot dischargegas from the compressor enters the leaving water side of the coaxialwater-cooled condenser/heat exchanger. This improves heat transfer bymaintaining a large temperature difference between the water and therefrigerant. Unfortunately, when the system switches to heating mode theheat transfer suffers because we lose the counter-flow heat transferbenefit. Method 1400 allows one of the two heat transfer fluids to bereversed in the coaxial heat-exchanger during the heating mode,increasing the efficiency of the system. The method 1400 begins in astep 1405.

In a step 1410, a heating or cooling command is received. The heatingand cooling commands can be conventional HVAC commands received by acontroller that are used to indicate a need for cooling or heating in anenclosed space (e.g., building).

In step 1420, the WSHP system is operated as a counter-flow heattransfer system for both cooling and heating. As such, in one embodimentthe controller sends a signal to reverse the flow of water through theheat exchanger for a heating cycle. Accordingly, instead of having aparallel-flow heat transfer system that is typically employed for heatcycles, the flow of water is reversed for the heating cycle to provide acounter-flow heat transfer system. The flow of the refrigerant at thecompressor is not altered with respect to conventional operation of aheat pump. Instead, in this embodiment the flow of water (also referredherein as the fluid) in the condenser coil is reversed in heating modeto provide counter-flow heat transfer. In this embodiment, the flow ofwater is not changed in a cooling mode since the water and refrigeranttypically flow in an opposite direction for a counter-flow heattransfer. Controllable valves such as the three-way valves in FIG. 3 canbe controlled by the controller to obtain counter-flow heat transfer forheating and cooling modes. In other embodiments, the direction ofrefrigerant flow or the direction of water can be reversed for eitherthe heating or cooling modes to achieve counter-flow heat transfer. Ineither of the embodiments, the controller can send a control signal tomanipulate the opening and closing of valves to control the directionsof flow. The method 1400 ends in a step 1430.

FIG. 15 illustrates a flow diagram of an embodiment of a method 1500 ofproviding an automatic anti-water hammer feature. The method 1500 can beused with the WSHP or with other HVAC or water systems that can sufferfrom water hammering. An accelerometer can be employed for the method1500. Additionally, a fully modulating actuator controlling anadjustable ball-valve, such as illustrated in FIG. 3 , can be used toadjust water flow and reduce or prevent water hammer. In someembodiments, a 0-10-volt signal can be sent to the actuator to adjustthe opening or closing profile of a valve during various operations.Ecto adjustable parameters can be used to adjust opening and closingprofiles. The accelerometer can be used to report vibrations duringdifferent operations and the controller can store these values and makeadjustments to valve opening based thereon to reduce the vibrations.Successful adjustments can be stored and used again. The method 1500,therefore, can prevent or reduce the possibility of braze-plate heatexchangers from freezing at unit start-up and RTUs from high-headpressure at the start of the cooling cycle. The method 1500 allows forcustomization to the opening/closing profile/timing to eliminate waterhammer effects on system piping. The method 1500 can be used with theWSHP or with other HVAC or water systems that can suffer from waterhammering.

The method 1500 begins in a step 1505. In a step 1510, vibrations aremeasured and recorded for various operating procedures of a watersystem. The water system can be a WSHP, another type of HVAC system or aplumbing system having pipes for water or fluid to flow therethrough.The vibration measurements are matched with the particular operationswhich can include opening or closing valves for start-up cycles, coolingcycles, heating cycles, flushing cycles, etc. An accelerometer ormultiple accelerometers can be employed to provide the vibrationmeasurements to the controller.

Record opening profile of controllable valves used in Q the variousoperating procedures in a step 1520. In one embodiment the controllernotes the how quickly or how slow a valve is opened for the variousprocedures and/or the amount in which the valves are opened. Theoperating speed and amount of opening can be controlled by varying thevoltage of a control signal sent to the various controllable valves.

In a step 1530, the opening profiles of valves are adjusted based on themeasured vibrations. A predetermined vibration level can be used tocompare the vibration measurements to, and adjustments can be made tothe opening profiles when the measure vibrations exceed the vibrationthresholds. As such, water hammer can be prevented or at least reduced.The method 1500 can be performed once during initial setup at aninstallation or can be performed throughout operation of a water systemto make adjustments when necessary. The method 1500 ends in a step 1540.

FIG. 16 illustrates a flow diagram of an embodiment of a method 1600 ofswitching between air-to-air and air-to-water WSHP systems. The method1600 is used with a heat pump that has both an air-to-air system and anair-to-water system. FIG. 18 illustrates such a system that includesboth an air-to-air coil and condenser coils. A controller can beconfigured to switch to the conventional air-to-air heat pump if thereare any problems with the WSHP. A controllable three-way valve can beused to select which heat exchanger to use. The method begins in a step1605.

In a step 1610, a determination is made to switch to an air-to-air heatpump. The determination can be based on alarms or warning signalsreceived at the controller with respect to the WSHP. The alarms orwarning signals include, water leaks, vibration problems, etc.

In a step 1620, a controllable valve is operated to change the heatexchanger from a WSHP to a heat exchanger of an air-to-air heat pump. Acontroller may direct the operation of a controllable valve to make theswitch. The method 1600 ends in a step 1630. On skilled in the art willunderstand the controller can also operate the controllable valve toswitch back from air-to-air to air-to-water heat pump.

Turning now to FIG. 18 , the hybrid air-to-air and air-to-water heatpump 1800 includes similar components to the WSHP 200 of FIG. 2 and aredenoted the same. Additionally, the hybrid heat pump 1800 includes anair condenser coil 1810, condenser fans and a hinged access panel 1830.Each of these components may be conventional components.

Additionally, the hybrid heat pump 1800 includes a discharge manifoldfor stage 1 1850 and a discharge manifold for stage 2 1840 that arecoupled to the air-cooled condenser coil 1810. A discharge refrigerantstream from compressor stage 1 1870 and a discharge refrigerant streamfrom compressor stage 2 1860 are also noted in FIG. 18 . A 3-way valve1880 is positioned to allow hot discharge refrigerant stream 1870 comingfrom stage 1 compressor to be routed either to stage-1 water cooledcondenser 206 or stage 1 air cooled condenser manifold 1850. A blow-upof the 3-way valve 1880 is provided that indicates the two differentmodes of employing the water-cooled condenser 206 (mode 1) or theair-cooled condenser 1850 (mode 2). When hot refrigerant bypasses thewater-cooled condenser 206 and is admitted instead into the air-cooledcondenser coil 1810, condenser fans 1820 are operated to draw outdoorair through the condenser coil 1810 and condense the liquid refrigerant.The liquid refrigerant exits the air-cooled condenser 1810 and reentersthe refrigeration system of the WSHP through a one-way check-valve 1890that is installed up-stream of the liquid filter drier 1895. By changingthe position of the 3-way valve 1880 the WSHP can select which condenserto use, either a water-cooled condenser 206 (or 204 for second stage) orthe air-cooled condenser 1810. The controller as disclosed herein canoperate the 3-way valve 1880 according to the method 1600 to switchbetween modes 1 and 2.

In this example we have identified one such stage of refrigerant,additional refrigerant discharge streams like 1870 from stage 2compressor would need another 3-way valve like 1880 connected todischarge manifold 1840. As such 3-way valve 1885 is also identified inFIG. 18 in the discharge stream 1860. An additional one-way check valvecan also be employed such as with check valve 1890 with stage 1. Each ofthe 3-way valves 1880, 1885, allow either fluid in the condenser coils204, 206, or refrigerant in the compressors for stages 1 and 2, givingthe WSHP unit the ability to switch between the different types of heatexchangers. One skilled in the art will understand the piping betweenthe various connections that are not illustrated.

In this embodiment we have described the unit operating in cooling modewhere hot gas is sent to condenser coils(s), the unit will work equallyas well in the heating mode when reversing valves 232 are used to sendcompressor hot gas to indoor coil of WSHP and the condenser coilextracts heat from either water entering the condenser coils 206/204 orcoil 1810.

The above-described methods may be embodied in or performed by variousconventional digital data processors, microprocessors or computingdevices, wherein these devices are programmed or store executableprograms of sequences of software instructions to perform one or more ofthe steps of the methods, e.g., steps of the methods of FIGS. 5-16 . Thesoftware instructions of such programs may be encoded inmachine-executable form on conventional digital data storage media thatis non-transitory, e.g., magnetic or optical disks, random-access memory(RAM), magnetic hard disks, flash memories, and/or read-only memory(ROM), to enable various types of digital data processors or computingdevices to perform one, multiple or all of the steps of one or more ofthe above-described methods, e.g., one or more of the steps of themethods of FIGS. 5-16 . Additionally, an apparatus, such as dedicatedWSHP controller or an RTU controller, may be designed to include thenecessary circuitry or programming to perform each step of the methodsof FIGS. 5-16 and include a memory to store the necessary operatinginstructions.

Those skilled in the art to which this application relates willappreciate that other and further additions, deletions, substitutionsand modifications may be made to the described embodiments.

What is claimed is:
 1. A controller, comprising: one or more processorsconfigured to: determine whether a water temperature in a condenser coilis above a first setpoint when a valve is open to a first flow settingthat permits warm water to flow to the condenser coil; and communicate afirst control signal, wherein content of the first control signaldepends on whether the water temperature in the condenser coil is abovethe first setpoint when the valve is open to the first flow setting;wherein, in response to a determination that the water temperature inthe condenser coil is above the first setpoint when the valve is open tothe first flow setting, the first control signal indicates to open thevalve to a second flow setting.
 2. The controller of claim 1, wherein,in response to a determination that the water temperature in thecondenser coil is not above the first setpoint when the valve is open tothe first flow setting, the first control signal indicates to turn onambient heating.
 3. The controller of claim 2, wherein the ambientheating comprises resistance heaters positioned proximate the condensercoil.
 4. The controller of claim 2, wherein the one or more processorsare further configured to communicate a low temperature alarm.
 5. Thecontroller of claim 1, wherein the second flow setting permits morewater to flow through the condenser coil than the first flow setting. 6.The controller of claim 1, wherein the one or more processors arefurther configured to: determine whether the water temperature in thecondenser coil is above a second setpoint when the valve is open to thesecond flow setting; and in response to a determination that the watertemperature in the condenser coil is not above the second setpoint whenthe valve is open to the second flow setting, communicate a secondcontrol signal via the interface, the second control signal indicatingto open the valve to the first flow setting.
 7. The controller of claim6, wherein the first setpoint corresponds to a lower temperature thanthe second setpoint.
 8. The controller of claim 7, wherein the secondsetpoint is selected to indicate when the water temperature in thecondenser coil is approaching a freezing condition.
 9. The controller ofclaim 8, wherein the second setpoint is selected based on a percentageof antifreeze and a type of antifreeze in the water flowing through thecondenser coil.
 10. A non-transitory computer-readable medium storinginstructions that, when executed by one or more processors, cause theone or more processors to perform actions comprising: determiningwhether a water temperature in a condenser coil is above a firstsetpoint when a valve is open to a first flow setting that permits warmwater to flow to the condenser coil; and communicating a first controlsignal, wherein content of the first control signal depends on whetherthe water temperature in the condenser coil is above the first setpointwhen the valve is open to the first flow setting; wherein, in responseto determining that the water temperature in the condenser coil is abovethe first setpoint when the valve is open to the first flow setting, thefirst control signal indicates to open the valve to a second flowsetting.
 11. The non-transitory computer-readable medium of claim 10,wherein, in response to determining that the water temperature in thecondenser coil is not above the first setpoint when the valve is open tothe first flow setting, the first control signal indicates to turn onambient heating.
 12. The non-transitory computer-readable medium ofclaim 10, wherein the actions further comprise: determining whether thewater temperature in the condenser coil is above a second setpoint whenthe valve is open to the second flow setting; in response to determiningthat the water temperature in the condenser coil is not above the secondsetpoint when the valve is open to the second flow setting,communicating a second control signal, the second control signalindicating to open the valve to the first flow setting.
 13. Thenon-transitory computer-readable medium of claim 10 wherein: the secondsetpoint is selected to indicate when the water temperature in thecondenser coil is approaching a freezing condition and the firstsetpoint corresponds to a lower temperature than the second setpoint;and the second flow setting permits more water to flow through thecondenser coil than the first flow setting.
 14. A Heating, Ventilation,and Air Conditioning (HVAC) system, the HVAC system comprising: awater-cooled condenser comprising a condenser coil; a valve configuredto permit warm water to flow from a stored water system to the condensercoil when the valve is open; and a controller configured to: determinewhether a water temperature in a condenser coil is above a firstsetpoint when a valve is open to a first flow setting that permits warmwater to flow to the condenser coil; and communicate a first controlsignal, wherein content of the first control signal depends on whetherthe water temperature in the condenser coil is above the first setpointwhen the valve is open to the first flow setting; wherein, in responseto a determination that the water temperature in the condenser coil isabove the first setpoint when the valve is open to the first flowsetting, the first control signal indicates to open the valve to asecond flow setting.
 15. The HVAC system of claim 14, wherein, inresponse to a determination that the water temperature in the condensercoil is not above the first setpoint when the valve is open to the firstflow setting, the first control signal indicates to turn on ambientheating.
 16. The HVAC system of claim 14, wherein the controller isfurther configured to: determine whether the water temperature in thecondenser coil is above a second setpoint when the valve is open to thesecond flow setting; in response to a determination that the watertemperature in the condenser coil is not above the second setpoint whenthe valve is open to the second flow setting, communicate a secondcontrol signal, the second control signal indicating to open the valveto the first flow setting.
 17. The HVAC system of claim 14 wherein: thesecond setpoint is selected to indicate when the water temperature inthe condenser coil is approaching a freezing condition and the firstsetpoint corresponds to a lower temperature than the second setpoint;and the second flow setting permits more water to flow through thecondenser coil than the first flow setting.